Scarlet Pimpernel

Yup. There were some pretty warm days the week leading into the St. Patrick's Day storm in 2014, and that was 2 weeks later too. Yeah a lot of that fell at night but it started in the afternoon and continued into early the next day. Plus, it was below freezing the entire following day. Not to mention the event on the 1st day of spring 2018, it was cool leading into it (below normal) but not extreme, it was the 3rd week of March, and that snow all fell during the daylight hours. And of course, March 2015 (same approximate time as this upcoming potential, 1st week of the month), where it rained the night before up to the morning of the event as a front went through, then a wave that went up the front dumped 6" snow on us...again, during the daylight hours as it turned colder.

Hessian bastards!! (and "Hanover", PA...sounds kinda German there!!!)

Dewpoints in July, you mean??? (especially 60s and 70s+!!!) It'll be here all too soon enough, don't you worry!

Officially a deer-topper!!!

Well, that could be offset by the other weenie rule: coming out of an extended cold period where the ground was covered in a glacier, add those couple inches back? So you sort of break even? You'll have to send some photos of your place (like your avatar picture), with what you get later today and tonight!

All joking aside, I'm just glad to see an expanded area of 6"+ through the region. At least, this looks larger than the 18Z cycle I think (haven't gone back to look at the other thread for the 18Z PBP stuff). The global models are not going to pick up on the fine-scale subtleties like banding and such, but this at least looks like a nice broad-brush.

Well, maybe true to a point. But a true "Nina screw job" would be something like "the storm which shall not be named" (Dec. 2010) where a coastal develops too far north or northeast for us in MD/VA and we smoke cirrus. In this case, that's not what's going on. The low is in a great spot. It's more an issue of the marginal temperatures in the DC-Balt corridor at the start really. We're not exactly lacking QPF amounts, in any model. ETA: If it were a bit cooler going into it at the start (not dealing with iffy temperatures early on), we'd all likely be looking at a high end warning. Yeah, over this way we may not get the potential 2+ foot totals that PHL-BOS and the eastern shore may get, but we'd probably be looking easily at up to a foot all the same. Even with subtle features like who gets the max bands, etc. Just that those are "magnified" more due to the temp issues early on.

Ahhh, thank you very much sir! That makes sense. Again, I do like the cluster of western solutions in there.

You don't even have to squint!!!

The control member of an ensemble system would essentially be a lower res version of the deterministic. Maybe @MillvilleWx meant that the ensemble mean is a bit to the east relative to the deterministic? At any rate, the main thing that I see is that there's a good clustering to the west there.

Hmm, I'm a bit confused or maybe I mis-read something. But @MillvilleWx said the EC was at the eastern end of the envelope of its own ensembles. The image you show where you add the deterministic EC (in blue) actually shows the opposite of that (it's in the cluster of the western solutions)?? Again, maybe I misunderstood what he was indicating before.

Great writeup in your WPC analysis, and great thoughts! I believe some pages back in this thread, someone posted the EC ensembles and they were clearly clustered more to the west and the deterministic was on the eastern end of the spread as you mention. Don't know if anyone posted the GEFS (if that's relevant), whether they're farther west than the deterministic GFS, etc.

Right...there's always a difference between "snowfall" and "snow depth". Obviously when it's cold, there shouldn't be huge differences, though you can have settling and compacting even in relatively short periods of time. But it's easy to accumulate a decent amount on, say, grassy surfaces (or a legitimate snowboard), only to have it compact down/melt/whatever and be less some hours later. All depends on rates with marginal temperatures. ETA: And I'm honestly not sure how those "positive snow depth" maps are generated or what algorithm is used.

This really is a tough situation especially taking temperatures into account, etc. I'm usually loath to be "critical" but I do find this to be a bit of an odd snowfall distribution. Some of the areas that are currently under a warning actually have less than warning criteria on that expected snowfall map. Also, just checking WPC's 50th percentile amounts, it has been showing significantly more (on the order of ~6-10" near DC, with higher as you go northeast and to the east of the Bay). I would absolutely not want to be on the hot seat making decisions on this, for sure!

Yeah...I generally just give a quick look for an overview on TT or some such site, plus it goes out farther than the 3km nest. But when honing in on things, 3km is typically the way to go.

Certainly for temperatures and thermal profiles at least.

Speaking of that 2nd storm in Feb. 2010 (Feb. 9-10)...I've shared this before, but out of all the photos I took during that incredible winter, this is my favorite. Cars still buried from the storm a few days earlier, almost seemingly groaning under the weight of yet MORE snow. And those snowflakes were like parachutes, plus temperatures were in the 20s with screaming winds.

First tropical system of the season???

Does it crash temps (relatively speaking) after 18Z sometime?

Maybe not "smoke" per se, but pasted with mashed potatoes sticking to every single surface if that verifies!!

I was just about to say, if this works out, a Sunday evening Jebwalk will be in order (with camera in hand)!!

Yup, exactly. We're not getting the crazy totals here in the DMV. I don't get the "disappointment" from some at models consistently showing around 6" or even a bit more around here, just because PHL-BOS might get 2 feet. Who cares, as long as we can do well, at least that's my feeling.

FWIW, I checked out WPC's page and here's what is indicated for the 50th percentile through 12Z Monday (24-h snow). Issued earlier this morning. So yeah, that other plot for some reason must be a higher percentile. Still, this looks pretty darned fine to me!